Header does not appear

I tried loading a header to my website via the header page. I also took out the text with the name of the site and the tagline. When I checked to see the changes, the header had been loaded but it did not appear on the top of the site. It was all blank. I suspect I have entered some CSS into the stylesheet that does not allow the header to appear, but I could not pinpoint if that is the case and which part of the code would be causing the header not to appear.

Does anyone have any suggestions as to what could the problem be besides CSS? and or how to fix it?